1. Field of the Invention
This invention relates to computer systems and, more particularly, to the management of snapshots or frozen images within distributed storage environments.
2. Description of the Related Art
Many business organizations and governmental entities rely upon applications that access large amounts of data, often exceeding a terabyte or more of data, for mission-critical applications. Often such data is stored on many different storage devices, which may be heterogeneous in nature, including many different types of devices from many different manufacturers. The storage devices may be physically distributed across one or more data centers, and may be accessible by a combination of networks such as local area networks (LANs), wide area networks (WANs), storage area networks (SANs) and the like.
Configuring individual applications that consume data, or application server systems that host such applications, to recognize and directly interact with each different storage device that may possibly be encountered in a heterogeneous storage environment will be increasingly difficult as the environment scales in size and complexity. Therefore, in some storage environments, specialized storage management software and hardware may be used to provide a more uniform storage model to storage consumers. Such software and hardware may also be configured to add storage features not present in individual storage devices to the storage model. Features to increase fault tolerance, such as data mirroring or data parity, as well as features to increase data access performance, such as disk striping, may be implemented in the storage model via hardware or software.
Among the advanced storage features provided by many vendors, the ability to create frozen images of storage devices has been increasing in importance. A frozen image of a storage device such as a volume or a file system may be defined as a representation or a logical copy of the device at a point in time. Frozen images may be utilized to support a variety of functions where an unchanging, internally consistent set of data may be required, including backups and off-line analysis (e.g., decision support and data mining). Numerous techniques to create frozen images, such as file system cloning, checkpoints, volume mirroring, and software and hardware snapshots, have been developed by different vendors. In enterprises utilizing a heterogeneous collection of operating systems, frozen image creation and access may require coordination of functions across multiple heterogeneous hosts and/or storage servers with varying functional and performance capabilities. As the amount of data managed within an enterprise grows, and as the population of users within the enterprise that may benefit from using frozen images grows, the number of frozen images desired or created using the different techniques available may also grow, potentially leading to a diverse collection of unshared, uncoordinated and possibly duplicated frozen images, some of which may not be easily accessible to the entire set of potential frozen image consumers. A hardware vendor-independent, operating system-independent unifying framework and service to help identify, characterize and manage the lifecycle of existing and potential frozen images may therefore be highly desirable in a distributed storage environment, especially if such a service is capable of operating with a variety of different file systems and volume managers from different software vendors.